The present invention generally relates to the field of check valves. More specifically, the present invention relates to check valves with substantially low sound when shutting off.
There is a constant search in the check valve industry to find new ways to help decrease the overall sound produced when a check valve operates and particularly when a check valve shuts off flow. Similar products on the market today create operational sound or noise during over all operation and when shutting off. The present invention delivers a substantially low sound or reduced sound check valve by providing a plurality of stages with a plurality of flaps. The plurality of stages may be a first stage and a second stage. The plurality of flaps may include a first and second flap that may be half circles with a space or slit between them and a third flap upstream or downstream when a fluid is in a forward flow, from the first and second flaps. The fluid includes fluids with solid particles and slurries.
The first and second flaps are arranged in a manner that prevents the third flap from closing quickly, thus substantially eliminating operational noise and shut off noise. And the third flap is not dependent on the arrangement of its location from the first flap and second flap, in other words the first and: second flaps can come first then the third flap or vise versa, when the fluid is in forward or reverse flow. A common application is a check valve used in conjunction with sump pumps removing ground water from foundation footings. In the past, when a check valve is used in a dwelling or any other application the overall operational noise would be elevated and may disturb occupants.